Boat lift

ABSTRACT

An apparatus and method are described for lifting a boat out of water. An improved boat lift having at least one support beam upon which the weight of a boat rests, the support beams having an interior wherein components of a cable drive system are mounted, provides lifting force through operation of the cable drive system, which withdraws the support cables to within the interior of the support beams, the cables attached at one of their ends to fixed points external to the beam.

This application claims priority from U.S. Provisional Application 61/161,649, filed Mar. 19, 2009, which is hereby incorporated by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to vehicle lifts, and more particularly to a mechanism for lifting boats.

BACKGROUND OF THE INVENTION

The cleaning, repairing and storing of a boat is most effectively performed by lifting the boat out of the water. To this end, boat lifts have been valuable and widely used. However, they tend to be unsightly, unstable and functionally inefficient.

A typical boat lift employs several pulleys and cables mounted overhead the boat, with the lifting mechanism (cable drive system) in an attic or upper part of an overhead dock or vertical beam structure. In these systems, cables extend from the overhead drive mechanism down to the boat support structure in the water. Not only are the cables unsightly, but so are the drive mechanisms; if they are not hidden in an overhead attic, they are mounted in plain view to a vertical beam structure or on a boat walkway. In addition, they are unstable because the cable lengths from the overhead system to the boat remain long, so that the boat tends to swing and sway in the wind particularly with the boat out of the water and in a raised position on the lift. Further, because of their structural designs, typical boat lifts are not able to provide lifting force proportional to the balanced weight of the lifted boat and so the boat may rise unevenly.

Examples of such boat lifts are shown in the figures; an overhead boat house lift is shown in FIG. 1 and a 4 (four) point boat lift is shown in FIG. 2. As shown in FIG. 1, an overhead boathouse lift 100 includes pulleys 102 that mount to the joists 104 or I-beams of an existing boathouse and utilize either a plurality of slings 106 or a cradle to support the boat to lift it out of the water. A cable drive system 108 is mounted to the upper part of the boathouse. Cables are routed across the upper part of the boathouse from the drive system 108 above the boat, to pulleys 102 on or beyond the width of the boat, and finally down to the supporting sling 106 or cradle.

FIG. 2 shows a 4 point lift 200 to include 4 (four) vertical beam structures placed near the sides of a boat dock, typically on existing wooden pilings 202 used for supporting a walkway 206. In some cases, as is the case shown in FIG. 2, the horizontal beam structures are omitted in favor of the support offered by the wooden pilings 202 themselves. Horizontal beams 204 rest on, or are mounted to, the vertical beam structures or wooden pilings 202, providing a fixed point for attaching cables 208. Vertical bumper guards are sometimes required with a 4 point lift to prevent damage to the boat or fixed structures when the boat “swings” in response to windy conditions. Cable drive systems 212 are mounted on top of pilings 202 on each side of the boat for the purpose of providing even lifting of the boat. Freestanding lifts are similar to the 4 point lift, where the vertical beams themselves rest on the bottom of the lake and reach from below the water line to above the boat hull.

A common complaint of these boat lifts is that the cables and drive system components are unsightly. In the arrangements stated above, the lifting mechanisms (i.e. cable drive systems) are attached far above the boat. The cables extend from the overhead drive systems down to the boat support structure in or near the surface of the water when the boat lifts are in a lowered position and remain visible even with the boat in a raised or lifted position on the boat lift. In the case of the boathouse lift of FIG. 1, the cable drive system 108 is attached to a joist 104 of the boathouse superstructure directly above the boat, and cables are clearly seen extending downward from the roof of the boathouse. Drive systems 212 of the 4 point boat lift of FIG. 2 are shrouded by a cover, but are still clearly visible in that their locations are not hidden from sight. Cables 208 are also clearly visible in either a lowered position or a lifted position.

Another disadvantage of prior art boat lifts is that they are unstable because the lifted boats tend to swing and sway in the wind due to the long cable length remaining between fixed points on the boat lift, even with the boat in a lifted position. Even in a lifted position, cables 110 of FIG. 1 extend from pulleys or rollers 102 mounted on the roof of the boathouse superstructure. The pulleys 102 act as a pivot point with the weight of the boat in the straps 106, creating a literal “swing” as the boat is in a lifted position. The 4 point boat lift of FIG. 2 is in a lifted position and cables 208 are long and easily seen and having an upper pivot point by their connection to the horizontal arms 204, again leading to a swing-like assembly

Further, because of their structural designs, typical boat lifts are not able to provide lifting force proportional to the balanced weight of the lifted boat and the boat may lift unevenly.

SUMMARY OF THE INVENTION

In accordance with the invention, many problems of prior art boat lifts are solved by mounting components of a cable drive system or mechanism to the support beams upon which the weight of the boat rests, and providing lifting force by withdrawing support cables within or around the cable drive system components, the cables attached at their external ends to fixed points external to the beam such that operation of the drive system causes movement of the support beams and attached drive system components.

In this way, the present invention provides a cleaner, more aesthetically pleasing structure because as the boat is in a lifted position, the support cables are nearly unseen, as are the drive system components. Further, it provides more stability, because in a lifted configuration, less cable length exists between attachment or contact points, reducing a “swinging” effect most notably observed in prior art boat lifts. Still further, it provides a more self-contained and inclusive support and cable drive mechanism assembly, allowing more versatility in the positioning of the support beams along the length of a boat, and thus, applying the lifting force in a more balanced manner.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more through understanding of the present invention, and advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows an isometric view of boathouse boat lift;

FIG. 2 shows an isometric view of a 4 (four) point boat lift;

FIG. 3A shows an isometric view preferred embodiment of the boat lift of the present invention in a lowered position

FIG. 3B shows the boat lift of FIG. 3A in a lifted position;

FIGS. 4A and 4B show the position of the lifts of FIG. 3A and FIG. 3B respectively, and additionally show a more clandestine placement of the cable mounting points;

FIG. 5 shows one embodiment of components of a cable drive system—a hydraulic cylinder and rod assembly, with attached pulley blocks and cables;

FIG. 6 shows the hydraulic cylinder and rod assembly of FIG. 5, with extension ends;

FIG. 7 shows a support beam of a preferred embodiment, with extension ends protruding from within its interior at each end;

FIG. 8 shows a front elevation view of a hydraulic cylinder and rod assembly in operation as a cable drive system in an extended, or lifted, configuration;

FIG. 9 shows a front elevation view of the hydraulic cylinder and rod assembly of FIG. 8, but in a retracted, or lowered, configuration;

FIG. 10 is an end elevation view of the support beam of FIG. 7;

FIG. 11 is an end elevation view of the extension end of FIG. 10 as mounted within the interior of the support beam

FIG. 12 is an isometric view of a hydraulic cylinder and rod assembly assembled with pulley blocks at each end;

FIG. 13 is a more detailed isometric view of one side of a pulley block of FIG. 12;

FIG. 14 shows another side of the pulley block of FIG. 13;

FIG. 15 is a planar view of the hydraulic cylinder, rod and pulley block assembly of FIG. 12;

FIG. 16 is the hydraulic cylinder, rod and pulley block assembly of FIG. 15, with cables;

FIG. 17A is a front elevation view of another preferred embodiment of a cable drive system for use with the present invention—utilizing inter-cogged cable spools;

FIG. 17B is a perpendicular view of the view of the cable drive system of FIG. 17, showing a motor that provides rotational force to one of the spools;

FIG. 18A is a cutaway view of a lead screw embodiment of the present invention;

FIG. 18B is a close-up view of the embodiment of FIG. 18A;

FIG. 19 is a front elevation view of another preferred embodiment of a cable drive system for use with the present invention—utilizing two axially opposed hydraulic, rod and pulley block assemblies;

FIG. 20 is a front elevation view of another preferred embodiment of a cable drive system for use with the present invention—utilizing two axially opposed hydraulic, rod and pulley block assemblies each mounted within separate extension members, both extension members attached to the interior of a support beam;

FIG. 21 shows a hook latch and wedge bolt, the hook latch mounted on or about the support beam of the present invention, and the hook latch having a pin for engaging with the hook latch;

FIG. 22 shows the hook latch engaged with the pin in the wedge bolt for retaining the support beam in a lifted configuration;

FIG. 23 shows a perspective view of a preferred embodiment of the present invention, with two support beam assemblies arranged near a boat dock to support the front and rear of a boat;

FIG. 24 shows a similar embodiment of FIG. 23, with an additional support beam placed aft to support the typically heavier portion of a boat;

FIG. 25 shows an embodiment similar to that of FIG. 23, with the exception of being arranged as a stand-alone assembly without being mounted directly to a boat dock; and

FIG. 26 shows a preferred embodiment similar to FIG. 23, as partially mounted to a walkway structure.

The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In accordance with at least one embodiment of the present invention, the problems of unsightliness, instability and functional inefficiency are solved by placing the components of a lift mechanism within the interior of hollow support beams upon which the weight of the boat rests, and providing lifting force by withdrawing support cables to within the hollow support beams, the external ends of the cables attached to fixed points.

In this way, the embodiment provides a cleaner, more aesthetically pleasing structure because as the boat is in a lifted position, the support cables are nearly unseen, as are the drive system components. Further, it provides more stability, because in a lifted configuration, less cable length exists between attachment or contact points, reducing a “swinging” effect most notably observed in prior art boat lifts. Still further, it provides a more self-contained and inclusive support and cable drive mechanism assembly, allowing more versatility in positioning the support beams, and thus, the lifting force.

A boat lift embodying the present invention generally includes a support beam member with a cable drive system preferably placed inside the support beam. Alternatively, the cable drive system may be placed on the exterior of a support beam, as long as it is attached to the support beam so that it moves with the support beam as a unit. The cable drive system provides lifting force by engendering vertical motion of the support beam to which it is attached. Because the drive components are within or along the support beam used to lift up a boat, the drive components preferably function under water. In the preferred embodiments shown in the figures and described below, cable drive systems generally operate by withdrawing cable length within or along the body of the support beam, thereby shortening the length of the cable extending beyond the body of the support beam. Because the exterior cable ends are attached to a fixed point, such as a dock or stationary post, the reduction in cable length outside the support beam causes the support beam to be pulled up toward the fixed point of the attached cable drive system, thus raising any structure being supported by the support beam (e.g. a boat).

Referring to FIG. 3A, a boat lift 300 embodying the present invention is shown to generally include a support beam body 302, out of which cables 306 (external lengths shown only) extend to attach at their external ends to elevated fixed points 330 so that when the external cable lengths are shortened, the support beam body 302 and all attached components are raised up to a position shown by FIG. 3B. In the embodiment depicted in FIG. 3A and FIG. 3B, the fixed point 330 to which the external ends of the cables 306 attach are located on stationary posts 322, the cables being held in place by a wedge socket assembly 308. The support beams 302, as well as other components of the present invention, may preferably be made of aluminum or stainless steel to resist corrosion.

Discussed in greater detail below, additional components may be preferred to aid in the operation of lifting a supported vehicle. Such additional components may include adjustable extension members 304 (described in greater detail below) which, in the embodiment of FIG. 3A, telescope into the interior of the support beam body 302 to adjust for a particular width defined by the distance between stationary structures such as posts 322 on either side of the support beam 302, or by the width of the vehicle to be supported on the support beam 302. In other words, the width defined by the cables 306 that extend from the support beam assembly to the elevated fixed points 330 is preferably greater than or at least the width of the boat to be supported by the boat lift 300.

Another additional component may include a perforated bar for easily attaching other components. For example, the support beam 302 is adapted for supporting the weight of a boat and preferably has a perforated bar 318 attached to its upper surface to allow the convenient attaching of hull skid supports 316 which are to contact the hull of the boat. One of ordinary skill in the art will appreciate that a perforated bar allows fasteners such as bolts and the like to attach other components that have corresponding holes such that the fastener aligns through both the holes of the perforated bar and the holes of the other component to matingly engage them.

The support beam is raised and lowered by a cable drive mechanism or system that withdraws cables 306 into the interior of the support beam 302. To this end, components such as pulley bearing assemblies 320 located at both ends of the support beam body 302 mounted on the extension members 304 are preferred to assist the cables in retracting and extending with minimal friction. A power unit 312, preferably a positive displacement hydraulic pump, supplies hydraulic fluid to cable drive components inside the support beam 302 of the cable drive system through hydraulic line 314. The power unit may be placed in a myriad of locations where one of ordinary skill in the art would find readily suitable. As shown in FIG. 3A, for example, the power unit 312 is placed upon a walkway 324. Other preferred locations may include more clandestine locations, such as beneath the walkway. The support beam 302 is shown as having a generally square-shaped and elongated cross section. Other shapes of elongated support beams including, for example, those with cross sections which are round or cylindrically-shaped are considered within the scope of a support beam usable with this and other embodiments. Whether square, cylindrical, or any other shape, those support beams which include an enclosed interior are termed “tubular” herein. Additionally, other preferred shapes of support beams may include “I-beams” or the like which do not have an enclosed interior, but generally have an “I” shaped or “T” shaped cross section, for example, and are also considered within the scope of the present application. In these latter shaped embodiments of support beams, the drive components attached to the support beam on any suitable surface of the support beam, albeit not within an interior.

Two or more support beams may be employed in a boat lift system for more evenly supporting the weight of an elongated vehicle such as a boat. The support beam positions are adjustable along the length of the particular boat upon installation because they tend to behave as separate lifting units and can be placed where needed. A typical preferred support beam assembly (a single support beam) has a capacity of about 5,000 lbs. (more typically 4,000-5,000 lbs.). In order to support more weight, one or more additional support beam assemblies may be added to the boat lift system. For example, if a user was required to lift a 20,000 lbs. boat, 4 standard beams could be used. If after installation of the boat lift, more lifting capacity is required, a user could add one or more support beam assemblies to the existing boat lift without needing to tear out the existing lift and install a completely new lift. The user only need connect the new support beam assembly to the power (hydraulic) supply and the external ends of the cables to fixed points as done with the other support beam assemblies.

It should be appreciated by those of ordinary skill in the art that the mounting point of the cable to an external, fixed point may be nearly anywhere above the vehicle to be lifted, whether it is in a visible location or a hidden one. It is preferable that, to provide an extra measure of cleanliness to the installation of the boat lift of the present invention, the cable be mounted in a less-observable location, such as beneath a walkway or boat dock structure, such as is shown in FIGS. 4A and 4B. Whereas the boat lift 300 of FIG. 4A is shown in a lowered position for accepting a boat upon its hull skid supports 316, FIG. 4B shows the support beam 302 in a raised or lifted configuration for lifting the supported boat above the water line 326. In this raised position, the boat lift 300 is more stable in comparison to the raised position of prior art boat lifts because the minimal slack permitted by the short cable length between cable pivot points 330 reduces the propensity for swinging commonly noted in prior art boat lifts. Additionally, because very little cable length is observable in the raised position, a cleaner aesthetic appearance is achieved. Further adding to the clean appearance, the mounting bracket 322, post structure or any other suitable mounting point for the cable can be very low profile, as opposed to prior art boat lifts that typically require fixed cable mounting points or pillars that extend far above the water line 326 as shown in as shown in FIGS. 1 and 2.

A preferred cable drive system is generally shown in FIG. 5. A hydraulic cylinder and rod (or piston) assembly 500 for withdrawing and extending cable from within or about the support beam body (as shown by the dashed lines) generally includes a hydraulic cylinder 508, an operatively and slidably affixed hydraulic rod 510, and attached pulley block assemblies 502 at each end of the hydraulic cylinder and rod assembly, one affixed to the cylinder 508, and another affixed at the opposite end of the assembly to the rod 510. Pulley block assemblies are discussed in greater detail below. As more particularly shown in FIG. 16, two cables are employed, one (reference numeral 1600) of which is fixed to the pulley block by clamp 1602 and spans the block back and forth 2 times before exiting the assembly and proceeding at its external end to an external fixed point (as shown in FIGS. 3A-3B). A second cable 1601 is attached to the hydraulic cylinder, rod and pulley block assembly in a similar fashion, wrapping around the assembly 2 times before exiting the assembly at the opposite end as did the first cable 1600. As described below, this arrangement whereby the cables are wrapped back and forth over the pulleys multiplies the corresponding vertical height displacement that results from the extension of the hydraulic rod

FIG. 12 shows a more detailed view of the cable drive components assembly 1200 which includes the combined components of the hydraulic cylinder 1202, rod 1204 and pulley block 1206. Particularly apparent in FIG. 12 are the pulleys 1210 and cable grooves 1208 of the pulley blocks 1206. Although cable grooves 1208 are shown to be substantially parallel to the long axis of the hydraulic cylinder, because the cables do not actually travel perfectly parallel across the assembly of the cable drive assembly 1200 (as particularly shown in FIG. 16), the groves 1208 may be canted to reflect the actual direction of the cables across the assembly 1200. The canting of the groves 1208 to be slanted slightly toward a lateral side of the assembly will reduce the wear on the cables, as will be appreciated by one of ordinary skill in the art. Also shown in FIG. 12 are hydraulic fluid input and output flanges 1212.

The operation of a preferred hydraulic cylinder and rod assembly for cable manipulation is more clearly shown in FIG. 8 and FIG. 9. In FIG. 8, the rod 804 of the hydraulic cylinder, rod and pulley block assembly 800 is extended from the cylinder 802. The cables 808 are operatively routed around pulleys of the pulley bock assemblies 806 and the length of cable around the assembly 800 is increased. Cables 808 extend from the cylinder, rod and pulley block assembly 800 through pulley bearing assemblies 810, and are ultimately attached to fixed points (uppermost end of the cables 808). As shown in FIG. 8, the assembly 800 is in a raised position when a reduced length of cable extends from the pulley bearing assemblies 810 and the fixed points 812, while the assembly 800 as shown in FIG. 9 is in a lowered position when an increased length of cable extends from the pulley bearing assemblies 810 and the fixed points 812. In FIG. 9, the rod is retracted into the cylinder, shortening the length around the cylinder, rod and pulley block assembly 800, and increasing the length of cable between the pulley bearing assemblies 810 and the fixed points.

As described above, the extending and withdrawing of cables is performed by increasing or decreasing the distance between at least 2 sets of pulleys, either increasing or shortening the length of attached cables around a hydraulic cylinder, rod and pulley block assembly and, therefore, shortening or increasing the length of the attached cables extending from the assembly. A preferred embodiment of the cable drive system of the presenting invention utilizes a hydraulic cylinder and rod assembly to this end, by extending the rod 510 to increase the length of cable 504 wrapped around the cylinder and rod assembly 500, or retracting the rod 510 into the cylinder 508 to shorten the length of cable 504 wrapped around the assembly 500. Preferably, each cable is routed around the hydraulic assembly at least 2 times, such that every inch of extension of the hydraulic rod (or piston) results in 8 inches of cumulative external cable length shortening, or 4 inches of vertical height displacement. However, based on this exemplary description, skilled persons can readily design different cable and pulley configurations to vary the factor by which the piston travel relates to beam travel. Moreover, skilled persons will also recognize that the driving force requirement will increase as a smaller movement of the piston causes a greater movement of the support beam.

In some embodiments, a cable drive system, or at least the moving components of a cable drive system, is connected to, in or around a weight supporting member so that they move together. Preferably, the moving components of the cable drive system, such as a hydraulic cylinder, rod and pulley block assembly, are placed inside of a support beam body. Referring to FIGS. 5-7, the hydraulic cylinder and rod assembly 500 can be attached inside a squarely-shaped and hollow support beam 700 so that the support beam 700 encapsulates the cylinder and rod assembly 500 with attached pulley block assembly 502 within its interior but allows cables 504 to exit the support beam 700. In this fashion, the cylinder and rod assembly 500 and pulley block assembly 502 are essentially hidden from sight. It should be understood, however, that a support beam need not encapsulate the cable drive system. That is, the cable drive system may be connected to the support beam's exterior or the support beam may also take the form of an I-beam or other structure that the cable drive system components are attached to, as long as the cable drive system is allowed to move with the beam.

As mentioned above, many embodiments of cable drive systems are contemplated as within the scope and spirit of the present invention. Examples of the preferred embodiments of the present invention are shown in FIGS. 17A through 20. FIG. 17A shows a preferred spool-type embodiment 1700 as generally including two cogged spools 1702 with intermeshing cogs 1704 axially extending about their circumferences. The spools are preferably located within the interior of the support beam body 1706 and are rotatably affixed to the support beam 1706 so that attached cables 1708 can be wrapped around them as shown in the FIGS. Both of the cogged spools 1702 may be powered, but both cogged spools may turn if only one of the two cogged spools 1702 is powered provided that the other non-powered spool is connected to the powered spool. As shown in FIGS. 17A and 17B, the cogs 1704 are intermeshed so that the motion of one spool 1702 engenders motion of the other spool 1702. In this embodiment as illustrated, the spools 1702 would rotate axially in opposite directions in operation. To this end, a power unit 1710 drives only one such spool. However, it should be understood that any plurality of gearing between the two spools could cause the rotational directions to be similar. Alternatively, gearing could be used to multiply motion to the spools using known gearing arrangements, as is appreciated by those of ordinary skill in the art.

Another preferred embodiment is shown in FIG. 18A and FIG. 18B where the cable drive system comprises a screw-type assembly. Lead screw assembly 1800 generally includes a centrally placed power unit 1810, which turns the lead screws 1802 on both ends of the power unit 1810. Cables are attached to traveling blocks 1804, which travel along the rotating lead screws 1802, drawing the traveling blocks 1804 inward or outward with respect to power unit 1810 and, thus, withdrawing or extending the attached cables. FIG. 18B is an enlarged view of the center portion of the lead screw assembly 1800 of FIG. 18A, showing how cable 1806 is preferably attached to the traveling block 1804 by a clamp 1808 on the end of the cable 1806. Also in this figure, it is shown that to ease movement of the traveling blocks 1804 within the support beam 1706, it is preferred that bearings 1814 are placed in contact between the traveling blocks 1804 and the support beam body 1706. The bearings 1814 may be ball bearings, roller bearings, or the like.

Another preferred embodiment is shown in FIG. 19. In this embodiment, dual opposing hydraulic assembly 1900 generally includes two hydraulic cylinder assemblies 1902. The assemblies 1902 each include a hydraulic cylinder, hydraulic rod and pulley block. As shown in FIG. 19, the assemblies 1900 are arranged opposite to each other so that the rods extend in opposite directions. This embodiment allows for greater lifting capacity of the single support beam they are mounted in, and/or increased cable withdrawal capacity because only a single cable is wrapped around each assembly 1902. The single hydraulic cable drive embodiments of previous figures typically require two cables to be wrapped around the hydraulic cylinder, rod and pulley block assembly, thereby allowing only half as many turns of cable as the embodiment 1900 of FIG. 19.

Yet another preferred embodiment is shown in FIG. 20. Dual extension hydraulic assembly 2000 generally includes two hydraulic cylinder, rod and pulley block assemblies 2002 each placed within extended extension members 2004, which extension members 2004 are slidingly placed within the interior of a larger interior dimensioned support beam 2006. In this embodiment, the width of the boat lift is proportional to the extending and retracting of the rods of the hydraulic cylinder, rod and pulley block assemblies.

Other components may be desirable for use in a more complete boat lift system in addition to the support beam. As shown in FIG. 7, a perforated bar 702 can be attached to the support beam 700 to allow the easy attachment of components to the support beam body. Such attachments may include, for example, boat hull skid supports 316 which are to contact the bull of the boat as shown in FIG. 3.

Extension members can be attached to the support beam ends, preferably routing the cables through pulleys to reduce friction of cable movement while the support beam is being raised and lowered. Extension members also allow the ability to more finely adjust the effective width of the support beam so that the cables do not come in contact with the sides of the supported boat. As shown in the embodiment of FIG. 3, adjustable extension members 304 telescope into the interior of the support beam body 302 to adjust for a particular width defined by the distance between mounting brackets (wedge socket assembly 308) on the stationary post 322 on either side of the support beam 302. The width is preferably greater than or at least equal to the width of the boat to be supported by the boat lift 300. As described above, the support beam is raised and lowered by a cable drive mechanism or system that withdraws cables 306 into the interior of the support beam 302. To this end, pulley bearing assemblies 320 at both ends of the support beam body 302 mounted on the extension members 304 are preferred to assist the cables in retracting and extending with minimal friction.

A perspective view of the extension member components is shown in FIG. 6, where extension members 600 are located at distal ends of the hydraulic cylinder assembly 500. As shown in FIG. 7, extension members 600 protrude from the interior of support beam 700 and are provided to allow an adjustment of width of the support beam 700. Extension members 600 preferably include pulley bearing assemblies 506 to assist in reducing friction of the cables as they are withdrawn and extended during the operation of the boat lift assembly comprising the support beam 700. As the extension members 600 may be of a smaller outer dimensions than the inner dimensions of the support beam 700, spacers 602 are provided to fill the gap and preferably also provide bolt contact points 604 where bolts contact that penetrate through the support beam 700 by through holes 704 in the support beam 700. Through holes 704 or bolt contact points 604 may be threaded holes or unthreaded as one of ordinary skill in the art deems appropriate to assure a clamping force to prevent the undesired movement of the extension members 600 once a desired width has been obtained.

Extension members 600 of FIG. 6 are also shown in FIG. 10. From this end view of the support beam 700, the extension member 600 and the pulleys of the pulley block 502 are visible, with cable 504. Further, FIG. 10 illustrates the components of the extension member 600, including the pulley bearing assembly 1008, which is held in the body 1000 of the extension member 600 by a pulley axle 1012, which itself is held in place by a pin (cotter pin, for example) 1010. FIG. 11 further shows fasteners, such as bolts or 1102, that are preferably provided to secure the extension member for this purpose. FIG. 11, as well as FIG. 7, also shows a sleeve 1104 for accepting a transverse member, as described below.

The pulley blocks of FIG. 12 are shown in greater detail in FIGS. 13 and 14. The cables are held in place as they pass around pulleys 1210 by cables grooves 1208. Depth of the center wall 1214 is short of the cable grooves 1208, so not to hinder their purpose. Four ball bearings 1300 are preferably placed in spherical detents at the corners of the body of the pulley block assembly 1206 so that when the pulley block assembly 1206 is located within the interior of the support beam, the bearings reduce friction of movement. Preferably, eight (8) ball bearings 1300 may be used. This is useful when the rod 1204 is being extended or withdrawn, and also serves to prevent binding of moving components within the support beam due to the weight of a supported boat (which would result in the pulley blocks 1206 twisting within the beam).

FIG. 15 shows, in a planar view, the hydraulic cylinder, rod and pulley block assembly of FIG. 12. As shown in FIG. 16 an end clamp 1602 can be used to secure one end of a cable to the cable drive system assembly 1200. The end clamp 1602 is placed on the end of a cable 1600 and the cable is drawn through a hole or groove of the pulley block 1208. As readily understood by one of ordinary skill in the art, the end of the cable 1600 with the end claim 1602 is prevented from being pulled through the hole or groove in the pulley block 1208.

As mentioned above in discussion of FIGS. 3 and 4, a latch including a hook attached to the support beam and/or extension members may be used to retain the support beam in a lifted position while relieving tension from the cables and pressure on the drive system components. FIG. 21 illustrates a preferred embodiment for this utility. A hook 2102 is swinglingly attached to the extension member 2112, which is attached to the support beam 2110. The hook 2102 latched upon the pin 2114 emerging from the cable wedge bolt assembly 2116, as shown in FIG. 22. Preferably, an arm 2104 is mounted on the perforated beam 2108 and attached to the hook 2102 to pull it toward the center of the support beam assembly to more easily engage the pin 2114. The hook 2102 may preferably have a rounded outer circumference to allow its displacement upon contact of a properly placed pin 2114, as will be appreciated by those of ordinary skill in the art. Also preferably, a spring 2106 is placed between the hook 2102 and the perforated beam 2108 to exert outward force on the hook 2102 for positive engagement on the pin 2114. FIGS. 21 and 22 also more clearly show the wedge socket 2116 for fixedly attaching one end of the cable, in which the cable is anchored to the fixed support by looping it through an opening, with a wedge positioned within the loop to maintain the cable in the fixed support.

FIG. 23 shows a perspective view of a preferred embodiment of the present invention, with two support beam assemblies arranged near a boat dock 2302. In this embodiment, one support beam assembly 2306 is placed aft to support the rear of a boat, while another 2304 is placed fore to support the front of a boat. In the embodiment shown in FIG. 23, the fore and aft support beam assemblies are connected to each other by transverse members 2308. The transverse members 2308 are preferably hollow and act as a conduit for hydraulic or electrical lines (not shown) providing power from the power unit (not shown) and the cable drive systems of the respective support beams. As shown in the embodiment of this figures, the cables are stationarily mounted (preferably via wedge socket assemblies discussed above) to support structures of the boat dock on both sides of the boat lift assembly.

FIG. 24 shows a similar embodiment to the one shown in FIG. 23, with an additional support beam 2402 placed aft (so that there are a total of 3 support beams) to support the typically heavier portion of a boat. Most boats include at least one engine to provide propulsion to the boat through the water. That engine is typically placed toward the rear, or stern, of the boat. This configuration tips the balance of the boat toward the rear. The placement of an additional support beam toward the rear of the boat lift assembly provides a more even lifting force.

Although it may be typical that the boat lift of the present invention is mounted to an existing structure such as a boat dock or walkway, it is within the scope of the present disclosure that the boat lift of the present invention may be utilized as a “stand-alone” unit, where it is not attached to an existing structure but is otherwise attached to stand-alone support members. Such an embodiment is shown in FIG. 25, where members 2502 are part of a stand-alone boat lift assembly 2500. Preferably, the stand-alone support members 2502 are adjustable in length so that they seat on a lake floor (or other water body floor) and provide an attachment point for the cable so that the boat may be adequately lifted out of the water.

As an ancillary benefit to the modular nature of some embodiments of the present invention, the components can be easily packaged for shipping. Applicant has found that the components of embodiments of the present invention preferably can be packaged into a shipping box with dimensions of 12″×12″×10′ allowing the loading of several packages into a bed of a typical full size truck. Further, very little manpower (typically two men) is required to assemble the components of some embodiments of the present invention to complete an operational boat lift.

As will be appreciated by one of ordinary skill in the art from this exemplary description, the boat lift of the present invention may be mounted in a myriad of positions, configurations and locations. Another such location may be, for example, along one side of a walkway 2600, as shown in FIG. 26. In this location, one side of the boat lift attaches to the walkway supporting structures while the other side may be attached to another structure or simply utilize a stand-alone support structure, as more prominently shown in FIG. 25.

The system describes herein provides the boating industry with a dependable solution for lifting a boat out of the water for docking and storage. The invention includes more than one novel and inventive aspect, and not all implementations will require all aspects to be combined in each implementation. Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. The invention is not limited to the use of boats or for the boating industry alone, but is useful in other areas, such as the automotive area, and in any environment where heavy equipment is desired to be moved from one position to another.

Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. For example, embodiments of the present invention are shown in the figures to be attached to a walkway or other existing structure. However, it is within the scope of the present invention that the embodiments may also be freestanding, that is, including a structure to mount fixed cable to or modifying an existing element of the embodiments without undue experimentation. Further, one of ordinary skill in the art will appreciate that while embodiments of the present invention are particularly drawn to boat lifts, it is within the scope of the present invention that embodiments are also capable of lifting other vehicles, such as cars, and can be used in other venues such as car garages. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. 

1. A boat lift, comprising: multiple support beams positioned apart to support a boat; at least one cable attached to each support beam and anchored to at least one fixed support to support the corresponding support beam; a lift mechanism attached to each of the multiple support beams, each lift mechanism when activated causing the cable to be drawn into or around the lift mechanism to cause the support beam along with the lift mechanism to move relative to the fixed support to raise the boat.
 2. The boat lift of claim 1 in which the multiple support beams each include an interior and in which the lift mechanisms are positioned within the interiors of the support beams.
 3. The boat lift of claim 1 in which the lift mechanism is hydraulically operated.
 4. The boat lift of claim 3 further comprising a single hydraulic pump that provides hydraulic fluid to the lift mechanisms on all of the beams.
 5. The boat lift of claim 3 in which each lift mechanism includes a hydraulic cylinder and a piston.
 6. The boat lift of claim 3 in which each lift mechanism includes at least two hydraulic cylinders and pistons.
 7. The boat lift of claim 3 in which each lift mechanism includes two spools that rotate to draw cable onto the spools, at least one of which is powered.
 8. The boat lift of claim 1 in which the beam includes at least one telescoping section for varying the length of the beam to allow the beam to span slips of different widths.
 9. The boat lift of claim 1 in which each lift mechanism includes: a hydraulic cylinder with a piston; at least two pulley blocks through which the cable is routed, one on either side of the hydraulic cylinder, so that extending the piston increases the distance between the pulley blocks to draw additional cable into or around the lift mechanism.
 10. The boat lift of claim 9 in which each beam is tubular and in which the hydraulic cylinder and the at least two pulley blocks are positioned inside the tubular beam.
 11. The boat lift of claim 10 in which one of the pulley blocks is fixed relative to the beam and the other one of the pulley blocks moves relative the beam as the piston moves in the cylinder, and further comprising a friction reducer to facilitate movement of the moving pulley block relative to the beam.
 12. The boat lift of claim 11 in which the friction reducer comprises a bearing positioned on the pulley block.
 13. The boat lift of claim 12 in which the friction reducer comprises a ball bearing positioned on at least four corners of the pulley block.
 14. The boat lift of claim 1 further comprising a latch for latching the beams to the fixed support to relieve tension from the cable when the boat is supported above the water line.
 15. The boat lift of claim 1 further comprising a single power source for supplying power to all the lift mechanisms, the power source distributing power to the lift mechanisms to ensure that all the lift mechanisms move the same amount regardless of different loads on the different lift mechanism to maintain the boat level in the boat lift.
 16. The boat lift of claim 1 in which at least one fixed supports is positioned on a walkway.
 17. The boat lift of claim 1 in which at least one fixed supports is positioned on a post extending from under the water line.
 18. The boat lift of claim 1 in which the cable is anchored to the fixed support by looping it through an opening, with a wedge positioned within the loop to maintain the cable in the fixed support.
 19. The boat lift of claim 1 in which the beam includes at least one extension section that extends from a main beam section and in which a hydraulic cylinder is positioned at least partly within the extension section.
 20. The boat lift of claim 1 in which the beam includes two extension sections and the lift mechanism includes two hydraulic cylinders, with a hydraulic cylinder positioned at least partly within each extension section.
 21. A lift system, comprising: a support beam for supporting a weight, the beam having an interior; one or more cables; a drive system for manipulating the one or more cables, wherein at least one component of the drive system is affixed within the interior of the beam, and a portion of the one or more cables affixed to the drive system such that such that operation of the drive system withdraws or extends the one or more cables into the interior of the beam.
 22. The lift system of claim 21 in which the portion of the drive system affixed within the interior of the beam includes a hydraulic press having a movable piston, the one or more cables in contact with the piston.
 23. The lift system of claim 21 in which the portion of the drive system affixed within the interior of the beam includes two or more spools, the one or more cables affixed to the two or more spools.
 24. The lift system of claim 22 in which the two or more spools include intermating cogs, the cog of one spool in contact with the cog of the other spool, such that rotation of one spool causes equal but opposite rotation of the other spool.
 25. The lift system of claim 23 having one cable, the cable having two opposite ends, each end affixed to a stationary object external to the interior of the beam, and wherein the portion of the cable affixed to the hydraulic press and movable piston is a center portion that encircles the hydraulic press and movable piston lengthwise, such that extension of the piston provides tension to the cable.
 26. A method for lifting a boat, comprising: providing at least one hollow beam; providing a drive system having a plurality of components; affixing at least one of the plurality of components within the hollow of the beam; affixing at least one end of a cable to a stationary point external the hollow of the beam; arranging one or more cables with the drive system, such that operation of the drive system causes the withdrawing or extending of the cables from within the hollow beam; and operating the drive system.
 27. A lift system, comprising: a support member for supporting a weight; one or more cables; a drive system for manipulating the one or more cables, wherein at least one component of the drive system is affixed to the support member, and a portion of the one or more cables affixed to the drive system such that such that operation of the drive system withdraws or extends the one or more cables, causing the support member and the attached drive system to move in accordance to the withdrawing and the extending of the cables.
 28. The lift system of claim 27, wherein the drive system is mounted to a bottom side of the support member.
 29. The lift system of claim 27, wherein the support member includes a reinforcement member to reduce flexing of the support member caused by a weight supported by the support member.
 30. The lift system of claim 27, further comprising adjustable ends adjustably fastened to distal ends of the support member for adjusting the effective width of the support member.
 31. The lift system of claim 27, further comprising rollers at distal ends of the support members, the rollers having a grove to support the cable, such that friction is reduced as the cable is moved during operation of the drive system.
 32. The lift system of claim 27, wherein the drive system includes a hydraulic piston cylinder and piston.
 33. The lift system of claim 27, wherein the drive system includes one or more spools having cylindrical surfaces, the one or more cables attached to the bodies such that rotation of the spools causes the cables to wrap around the bodies.
 34. A cable fastening assembly comprising: a wedge having a groove along which a cable may align, the wedge having a tapered end and a wide end; a mount having a slot for accepting the wedge and having means for attaching to a surface, wherein the slot is large enough to accept the tapered end of the wedge, but prevents the wide end of the wedge to be pulled fully through the slot, and wherein providing a cable through one end of the slot and along the groove of the wedge, and providing force to the cable to position the wedge in the slot causes the cable to bind. 